JPH03216431A - Paper sheet feeding device - Google Patents

Abstract

PURPOSE:To prevent the double feed of paper sheets by mounting a means to cut off an air passage at a gap between endless belts on the tip part, in a paper sheet feeding direction in a sheet loading range, of a sheet, in a vacuum suction type sheet feeding device. CONSTITUTION:A protrusion part 11 not protruded from the upper surface of an endless belt 1 and having height enough for closing an air passage E is formed at a gap 10 between endless belts 1 on the surface of a vacuum tank 3 and on the tip part, in a sheet feeding direction D in a loading range S, of a sheet 5. Since an air flow generated through rotation of a fan 4 for suction flows only in the direction C, a suction action is exerted in the loading range S on the loaded sheets 5 in a state that tips are trued. This constitution prevents the occurrence of a double feed due to the endless belt 1 along with rotation of a drive roller 2a, and feeds sheets, in order, from a sheet 5a at a lowermost level.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paper feeding device used in copying machines, facsimile machines, printers, etc., which suctions and feeds sheets in sequence starting from the lowest stacked sheets. .

[Conventional technology]

Fig. 9 is a front view showing a conventional vacuum suction type paper feeding device, Fig. 10 is a plan view of Fig. 9, Fig. 11 is a side view of Fig. 9, and Fig. 12 is an E-line of Fig. 10. A cross-sectional view,
1 is an endless belt in which a large number of suction holes 1a are formed;
2a and 2b are a driving roller and a driven roller that support a plurality of endless belts 1 in parallel; 3 is a vacuum tank installed between the driving roller 2a and the driven roller 2b;
3a is a suction hole formed on the surface of the vacuum tank 30;
4 is a suction fan installed inside the vacuum tank 3; 5 is paper stacked on the endless belt 1; 6 is a suction fan installed inside the vacuum tank 3;
7 is a back fence that holds the paper 5 within the paper loading range;
is a pair of feed rollers installed downstream of the endless belt 1 in the paper feeding direction.

In FIGS. 9 to 12, among the loaded utensils 5, the lowermost utensil 5a receives the suction force generated by the rotation of the suction fan 4, that is, the suction hole 1a. 3a, the surface of the vacuum tank 3 between the endless belts 1, and the duct part A, which is composed of the duct 5, is sucked in the direction of the endless belt 1,
Furthermore, due to the rotation of the drive roller 2a, the endless belt 1
The paper is fed in the direction of the feed roller pair 7. and,
Thereafter, sheets of paper are sequentially fed in the same way starting from the lowest one of the stacks 5a.

[Problem to be solved by the invention]

In the above-mentioned conventional apparatus, when the stacked yoke 5 is in a poor loading condition, as shown in the explanatory diagram of the double feeding state in FIG. If the paper 5b is retracted from the leading edge, the paper 5a,
5b double feeding occurs.

In other words, double feeding of paper may occur because the weight of the paper sheet 5 placed on top of the sheet is added to the paper sheet 5a at the lowest position, and the paper sheet 5a at the lowest position is not separated from the paper sheet 5b above it. This occurs when static electricity accumulates on the paper and paper cannot be separated properly.

Further, as shown in the explanatory diagram of the air flow caused by the suction fan 4 shown in FIG. 14, the air flow passes from the front and back direction of the loaded portion of the yoke 5 through the air passage E in the gap between the endless belts 1, and is shown by the arrow B. As shown in C, air is sucked by the suction fan 4 and flows into the vacuum tank 3. However, among the airflows, the airflow B from the paper feeding direction (direction of arrow D) of the paper feeder 5 is
This may cause the leading end of the paper 5 in the paper feeding direction to deviate from the predetermined paper stacking number range S, and this positional shift of the leading end of the paper 5 causes double feeding.

The above-mentioned double feeding of the paper 5 is a problem as it causes copying defects, copy page errors, page shortages, etc.

SUMMARY OF THE INVENTION An object of the present invention is to provide a paper feeding device that can prevent stacked papers from being fed multiple times.

[Means to solve the problem]

The above purpose is to provide a feeder that is equipped with a plurality of endless belts and a vacuum tank with vacuum suction holes provided in the gaps between the endless belts, and feeds paper by suctioning it sequentially starting from the lowest sheet stacked on the endless belt. This is achieved by configuring the paper device to block the air passage in the gap between the endless belts at the leading end in the paper feeding direction of the paper stacking range.

[Effect]

The leading edge of the stacked paper in the paper feeding direction will no longer shift from the paper stacking range due to the airflow, and the paper will be sufficiently suctioned, allowing the vacuum tank and endless belt to separate and feed the paper well. It will be done.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 3 is a block diagram showing the schematic structure of a copying machine to which an embodiment of the present invention is applied, and 20 is an automatic document feeder (AD).
F), 2 1 is the main body of the copying machine, 22 is a belt-shaped photoreceptor, 23 is an exposure section, 24 is a charging section, 25 is an eraser, 26
27 is a developing section, 27 is a transfer/separation section, 28 is a cleaning section, 29 is a fixing section, 30 is a plurality of feeding trays, and 31 is a double-sided sheet discharge unit, which performs a known copying operation.

FIG. 4 is a configuration diagram showing the detailed configuration of the ADF 20,
■ is endless belt, 32 is contact glass, 33
34 is a conveyance belt, 34 is an intermediate conveyance roller, 35 is a paper feed roller, 36 is a document table, 36a is a side guide, 36
b is an end plate, 37 is a reversing part, 38 is a double-sided branch claw, 39 is a branch claw for manual document feeding (SADF), 40
4 is a reversing/input/discharging roller, 41 is an SADF discharge roller, 42 is a right turn roller, and 43 is a registration gate claw.

FIGS. 5(a) to 5(f) are explanatory diagrams of the document conveyance operation, and FIG. 5(a) shows the conveyance state in SADF mode, and the document is placed in contact with the side to be copied facing down. It is set on the right side of the glass 32, and the conveyor belt 33 is moved in the direction of the arrow.
The contact glass 32 is conveyed by a known exposure operation on the contact glass 32, and is discharged by a discharge roller 41.

5Tb) to (C) show the conveyance state of the ADF in the single-sided original mode, where the original is set on the original table 36 with the side to be copied facing down, and is subjected to the action of the endless belt 1, which will be described in detail later. while reaching the paper feed roller 35, and further reaches the intermediate conveyance roller 34. It is conveyed to the contact glass 32 by the right turn roller 42, stops on the contact glass 32, and is exposed to light over the entire surface (Fig. 5, mountain)]. The exposed original is sent to the reversing unit 37, switched back, and placed on the original table 36 with the copied side facing down.
Return to [Figure 5 (C)].

FIGS. 5(d) to 5(f) show the conveyance state of the ADF in the double-sided document mode, in which the document is set in the same way as in FIG. 5(b), and is conveyed to the reversing section 37 after being exposed to light. [Fig. 5(d)] After the switchback, the contact glass 32 is conveyed again by the double-sided branching claw 38 and stopped, and the back side is exposed and sent to the reversing unit 37 [Fig. 5(e)] )
]. The original sent to the reversing unit 37 passes through the reversing unit 37 and is returned to the original table 36 as it is [FIG. 5(f)].

6 is a perspective view showing the configuration of the document table 36 portion, and FIG. 7 is a perspective view showing the blower mechanism, in which 36a is a side guide, 36b is an end plate, 50 is an ADF blower motor, and 51 is an air circulation 52 is a gate valve, 5
3 is a gate valve solenoid, 54 is a document partition plate sensor, 5
5 is a document presence/absence sensor, and 56 is an air knife casing.

In FIGS. 6 and 7, this document feeding method separates the leading edge of the document using an air knife and belt-feeds the document by air suction.
6a to center the original, and end play}36b
It is necessary to set the leading edge of the document in a predetermined position. When the end plate 36b is aligned according to the size display on the side guide 36a, the leading edge of the document is positioned above the document partition plate sensor 54, and the ADF mode is set when the document presence/absence sensor 55 detects the document.

FIG. 8(a) is an explanatory diagram of the separation operation of the leading edge of the document. The air knife casing 56 has six holes, and air is blown toward the center of the document by the ADF blower motor 50. ing. From the start to the end of the ADF mode, the ADF blower motor 50 continues to blow air to prevent double feeding during document sorting and feeding.

FIG. 8(b) is an explanatory diagram of the paper feeding operation, and when the document handling by the ADF prower motor 50 is completed,
The gate valve solenoid 53 is operated, the gate valve 52 switches the air flow path 51, and the lowest document is attracted to the surface of the endless belt 1. Next, the endless belt rotates and conveys the document to the paper feed roller 35.

As shown in FIG. 7, the ADF blower motor 50 performs the above-described air knife separation and paper feeding by air suction by installing two thin sirotsukko fans in one promoter motor. uses a brushless DC servo motor with low wear, noise, and electrical noise, ensuring long life and high reliability.

Further, the gate valve solenoid 53 operates when a document is sucked as described above, and when the gate valve solenoid 53 is OFF, the gate valve 52 is located at the position shown by the broken line in FIG. The document is not suctioned. Furthermore, when the number of repeated sheets is 9 or more, the gate valve solenoid 53 is automatically turned OFF and turned ON again from the last 6th sheet during the repeat, thereby preventing the occurrence of wrinkles in the document while it is waiting to be fed. .

FIG. 1 is a plan view of essential parts of an embodiment of the present invention, and FIG.
13 is a front cross-sectional view of the illustrated embodiment, in which members corresponding to those described in FIGS. 9 to 13 are given the same reference numerals.

Figure 1. In FIG. 2, the vacuum tank 3
In the gap 10 between the endless belts 1 on the surface (paper 5 loading side), a protrusion 1l is formed with a height that is high enough to close the air passage E without protruding from the upper surface of the endless belt 1. The air passage E is blocked so that air is not sucked from the D side and introduced into the vacuum tank 3.

Therefore, for the sheets 5 stacked in the stacking range S on the plurality of endless belts 1, the lowest paper 5a is located above the protrusion 11, and when the suction fan 4 starts rotating, the air flow is directed in the paper feeding direction. Only flow C flows from the direction opposite to D. Therefore, the stacked sheets 5 are sufficiently suctioned by the suction fan 4 with their leading edges aligned in the sheet stacking range S, and are moved in the sheet feeding direction D by the endless belt 1 due to the rotation of the drive roller 2a. The sheets are fed sequentially starting from the lowest sheet 5a.

As described above, the protrusion 11 is formed as an obstacle wall in the gap 10 between the endless belts 1 in order to support the paper suction air passage E only within the loading range S of the belt 5. 11 can be formed by forming a part of the vacuum tank 3 by drawing or by bonding a block body between the endless belts 1.

The protrusion 11 is set at a height that does not obstruct the sheet feeding operation by the endless belt 1 and can block the air passage (air duct) E between the endless belts 1.

〔Effect of the invention〕

As explained above, according to the present invention, by blocking the air passage at the leading edge in the paper feeding direction of the paper loading range, the leading edge of the paper is prevented from shifting due to air flow, and the paper is sufficiently sucked. Therefore, it is possible to provide a paper feeding device that can prevent double feeding when feeding stacked papers.

[Brief explanation of drawings]

FIG. 1 is a plan view of essential parts of an embodiment of a paper feeder according to the present invention, FIG. 2 is a front sectional view of the embodiment of FIG. 1, and FIG. 4 is a configuration diagram showing the detailed configuration of the ADF, FIG. 5 is an explanatory diagram of the document transport operation, FIG. 6 is a perspective view showing the configuration of the document table portion, FIG. 7 is a perspective view showing the blower mechanism, and FIG. The figure is an explanatory diagram of the separation/feeding operation, Fig. 9 is a front view of a conventional paper feeding device, and Fig. 10 is a 9th
11 is a side view of FIG. 9, FIG. 12 is a sectional view taken along the E-I line of FIG. FIG. 2 is an explanatory diagram showing airflow according to 1... Endless belt, la, 3a... Suction hole,
3... Vacuum tank, 4... Suction fan, 5
... Paper, 10 ... Gap between endless belts, 1
1.゜Protrusion, D...Paper feeding direction, E...Air passage, S...Loading range. No.! Figure 2 Figure 3 Figure 4 Figure 2 4/4C) j9 38 j:) j4
jZjj +54 Imaichi Fig. 6 Fig. 7 Fig. 8 lσ Norb No. 1/Fig. 9 Fig. 10 Fig. l2

Claims (1)

[Claims] In a paper feeding device that includes a plurality of endless belts and a vacuum tank having vacuum suction holes in gaps between the endless belts, and sequentially suctions and feeds sheets of paper stacked on the endless belts starting from the lowest one, A paper feeding device characterized in that a means is provided for blocking an air passage in a gap between the endless belts at a leading end in a paper feeding direction of a paper loading range.